In recent years the cable television industry has grown tremendously, with the likelihood of continuing to grow in future years. Future growth could enable the cable television industry to provide hundreds, possibly thousands of cable television channels to consumers. As the cable television industry consumer base has grown, it has become increasingly important to minimize breakdowns in cable television systems in order to avoid loss of service to customers.
Typically, a cable television system includes a location for receiving and distributing program signals, which are broad band radio-frequency (RF) signals (i.e., 5 MHz to 1000 MHz). This location is commonly known as a headend where incoming program signals are received from sources such as a satellite dish, an antenna, a VCR tape, and the like. For most incoming broad band signal channels, the headend has individual modulators for modulating each of the signals to the appropriate frequency band for its particular channel. The modulators each provide output signals that are fed into a combiner network. The combiner network combines all of the signals received from the various channels on one wide band of frequencies. Because signals lose approximately 3 dB for every two signals combined, the combined signal output must be amplified to compensate for the loss. A high-powered amplifier amplifies the combined signal to produce an amplified combined signal which is then transmitted to a splitter network. The splitter network divides the amplified combined signal into numerous signals for distribution to multiple locations.
Amplifiers in the headend are prone to breakdowns and operational failures because such amplifiers must run at high power levels to reduce signal distortion. The high power levels produce heat that can cause degradation of the semi-conductors and, ultimately, amplifier operational failure. Because the headend may be operated electronically from a remote location, it is often unattended by a human operator. Currently, the failure of one amplifier in a headend may affect more than 100,000 customers. Service to the affected customers is delayed until a human operator is dispatched to correct the problem. Such delays are expensive to the cable television industry and result in customer frustration and dissatisfaction.
The present invention provides a solution to these and other problems and offers advantages over the prior art.